for the answer we turn to science. >> the estimate is that there's about 200 genes that actually make up the facial composition so if you think about a slot machine, what are the odds you would get 200 rows on a slot machine to line up. >> reporter: what's the number? what are the chances that i have a twin out there who looks exactly like me. >> 1 in a billion. >> reporter: 1 in a billion with a "b." . do people tell you look like anybody? >> oh, you look like elizabeth taylor when you were young or fran dresh sneer do i look like anybody famous? >> you look like you because you are famous. >> reporter: oh, my gosh, i love you. so the next time someone tells you look look like -- >> kevin durant. >> robert downey jr. >> jennifer lopez. >> this little guy they say he looks like bruce willis. >> reporter: i see it, i see it, really. >>> and there it is, and there is truth behind it. we all have a number of genes to make up our facial features, and if someone shares a similar number of genes, that's why we end up looking alike. >> amazing. >> reporter: i know you are getting tweets all